In moderate climate zones, utility meters, particularly water meters, are located in subsurface ground enclosures in areas near residences or other dwellings. Such enclosures are referred to as “pits.” An example of such enclosure is illustrated in Cerny et al., U.S. Pat. No. 5,298,894, issued Mar. 29, 1994, and assigned to the assignee of the present invention. In these systems, a transmitter or transceiver, and an associated antenna, are enclosed in one or more sealed enclosures which are located in a larger pit for the water meter. In Cerny et al., the antenna was disposed in an upper compartment and the electronics was installed in a lower compartment with a double seal between the two parts.
A primary issue concerning all remote meter systems, whether used in pit installations or elsewhere, is their resistance to weather, and to submersion in the event that the pit fills with water. Therefore, the invention provides a device that is very resistant to moisture conditions in its operating environment. Typically, the data storage device is powered by one or more batteries, which must also be contained in a sealed enclosure.
In Bloss, Jr. et al., U.S. Pat. No. 5,877,703, a utility meter transmitter assembly has three vertically arranged compartments with a lowermost compartment receiving potting material to seal some wire entry points. A portion of potting material was injected through a port into the bottom compartment. A battery was encapsulated separately in a battery assembly that was inserted into a lower compartment from the bottom. In Bloss, Jr. et al., U.S. Pat. No. 5,825,303, the housing for the electronics is provided by a tube and the encapsulating material is injected through a bottom opening to encapsulate the electronic circuit board and the battery. Bublitz et al., U.S. Pat. No. 6,378,817 discloses a bracket for mounting components in a subsurface ground enclosure.
The present invention provides an improved method of encapsulation and an improved sealed transmitter assembly for installation in a subsurface ground enclosure. As with other electronic devices, there is a desire to make the devices smaller in size, lower in the cost of manufacture, and easier to service in the field.
Here, it is required that the transmitter be suitable for fixed installations and therefore utilize more power and radiating energy, so as to transmit over longer distances than in a mobile system. This requires a somewhat larger antenna. The technical problem is how to accommodate the large antenna and the batteries in a small size, sealed package.